A crash cushion, also known as an impact attenuator, protects vehicles from damage when they collide with a structure. It can also save the lives of people inside the vehicle. The cushion absorbs kinetic energy and can potentially redirect the colliding vehicle away from danger. These cushions are helpful for construction projects, as well as buffers to control traffic.
One of the main reasons for crash cushions is to limit the damage that can occur on highways. Crash cushions are often placed in front of gore points and near overpasses. A gore point is part of a freeway exit, such as where white lines form a v-shape with landscaping in the middle.
Crash cushions can be used over and over. They are composed of different sections that are designed to collapse into each other while absorbing the impact of a crash. The cushions typically maintain their normal appearance following the collision. But cushions also often need to be repaired or replaced by state officials.
According to the Texas Department of Transportation, the average cushion absorbs a half dozen hits per year. The state has found about ten hot spots where cushions are hit often. The state spends about $400,000 every month to repair these damaged cushions and is partially reimbursed through insurance companies.
One of the main reasons cars hit crash cushions in gore points and along the roadside is because drivers become distracted or overcorrect. They may be paying more attention to their smartphone, dashboard controls, or become distracted when they are lost and looking for signs to read. Sometimes when drivers are new to an area they can get confused by signs at the last minute and swerve into an exit lane.
Intoxication or speeding and losing control are other reasons why drivers collide with railings or other barriers. These crashes are more likely to happen at night when visibility is reduced. Busy freeways in rush hour traffic can lead to drivers attempting short cuts that send them crashing into crash cushions.
There are several different types of barrier systems which can be used as crash cushions. They can comprise various attenuators that form a gate along the side of a highway. Sometimes water-filled barrels or similar objects serve as attenuators. Water-filled attenuators are typically not anchored to the ground, making them easy to set up and remove.
A Fitch barrier, which comes from the auto racing world, is a plastic barrier filled with sand. A barrel filled with 1,400 pounds of sand can be very effective at limiting the damage of a car crash.
NCHRP 350 and EN 1317 are standards that help make highway barrier systems more durable. These barriers divide opposing traffic and are often used during construction work. Some metal barriers are designed to be temporary while others are designed to last for many years. Anchored barriers are more expensive, but are safer because they are designed to stabilize the impact from a collision.
You’ve probably seen truck-mounted attenuators on the highway. The attenuator is shaped like rectangle box towed by a truck. It can be parked on the side of the road during maintenance as a barrier to protect workers. The Arizona Department of Transportation uses truck-mounted attenuators, which they say save many lives every year.
To learn more about attenuators or other roadway products, contact Zumar.